There are a number of instances, inclusive of injuries, surgery and the like, for which cold therapy is prescribed. To this end, water circulating pads have been devised in various sizes and shapes to be applied against or wrapped about a body part to be treated. Each pad has an inlet and an outlet and a path within the pad extending between the inlet and the outlet. Cold water can thereby be introduced into the pad, circulated through the pad, and removed therefrom.
In recent years there has been a marked increase in sports activities, for example, and a marked increase in a number of people participating therein. As a result, there has been an increased demand for a simple, portable, cold therapy system, capable of use in the home or elsewhere. It will further be understood that the use of such systems is not limited to sports injuries.
Prior art workers have devised a number of cold therapy systems in an attempt to meet this demand. One approach is to provide a pad for application to the body area to be treated, a cooler filled with ice and water, and a tube extending from the cooler to the pad. The cooler is held above the pad so that chilled water is introduced into the pad from the cooler by gravity. As the chilled water in the pad warms from body heat, the cooler can be placed in a position below the pad, causing the pad to drain into the cooler. After a short time the water is recooled by the ice in the cooler and the process may be repeated. Such a system requires considerable manipulation by the user, and does not provide an even, controlled cold temperature at the treatment site.
Recently, a number of prior art workers have devised cold therapy systems wherein cold water is continuously circulated from a reservoir through a pad and back to the reservoir by means of a pump. A number of these systems have means for regulating the temperature of the water passing through the pad. An early approach, for example, was simply to regulate the temperature of the water, itself, within the reservoir. Another approach is described in U.S. Pat. No. 5,241,951. This reference teaches the provision of a reservoir and a pump submersible therein. The outlet of the pump is connected to the inlet of the pad by appropriate conduit means. The outlet of the pad is connected to the reservoir by a suitable return conduit. Temperature regulation is achieved by an in-line valve in the form of an adjustable flow restrictor located in either one of the conduits, but preferably in the return conduit. By closing the valve to reduce the flow rate of the fluid, temperature in the pad increases due to heat transfer. By opening the valve to increase the flow rate, temperature in the pad decreases. Since the flow restrictor valve is in the form of a stop cock valve, precise adjustment and precisely repeatable adjustments are difficult, if not substantially impossible, to make.
U.S. Pat. No. 5,476,489 entitled COLD THERAPY SYSTEM there is taught a system comprising a reservoir incorporating a cooler having insulative walls, an insulative bottom, and an insulative closure lid. A non-submersible pump and a housing therefore are attached to the exterior of one of the cooler walls. The inlet of the pump is connected to the reservoir and the outlet of the pump is connected to a treatment pad through an insulated delivery tube. The pad is connected by an insulated return tube to the reservoir. The insulated return tube may have a liquid crystal temperature indicator located therein. The pump is of a multi-speed design, enabling control of the water temperature within the pad by means of flow rate, eliminating the need for an adjustable flow restricting valve. For reasons made evident hereinafter, the teachings of this co-pending application are herein incorporated by reference. A problem encountered with this approach is poor pump performance at extremely low speeds.
The present invention is directed to a cold therapy system which overcomes a number of these deficiencies of the prior art systems. According to the present invention, a reservoir for water and ice is provided in the form of a standard cooler having a closure lid. The reservoir is connected to a treatment pad through a non-submersible pump and an insulated delivery tube. The pad is connected by an insulated return tube to the reservoir. The pump is mounted in a housing affixed to the exterior of the cooler so that the ice and water are isolated from any heat generated by the pump.
The pump of the present invention is of a single-speed design. As will be described more fully hereinafter, control of the water temperature in the pad is accomplished by running the pump in any one of a number of selectable intermittent modes. In this way the water temperature is more precisely controlled in a repeatable manner. Furthermore, the problems encountered when running a pump at very low speeds are eliminated. The delivery tube is provided with a check valve and the return tube is provided with a flow control orifice or other appropriate restriction means, for reasons set forth hereinafter. Finally, the system may be provided with a temperature indicator located in either the delivery tube or return tube.